What is a stop loss order and how does it work on futures?
A stop loss order waits at a price worse than your entry and becomes a market or limit order when the market trades there. The stop price is a trigger, not a fill price: slippage and gaps can fill it further away, so the planned loss is a floor, and stop distance and contract count must be set together.
By Soren Huang · Published · updated · Editorial policy
Contents
- What is a stop loss order and how does it work?
- Stop market vs stop limit: which one should a futures trader use?
- Why can the fill be worse than the stop price? Slippage and gaps
- How to place a stop loss order on a futures platform
- How far should the stop be? Testing stop distance in a backtest
- What a stop loss cannot protect you from: leverage and margin
- Frequently asked questions
- References
What is a stop loss order and how does it work?
A stop loss order is a resting exit order placed at a price worse than your entry. When the market trades at that price, it becomes a market order (or a limit order) and closes the position. The stop price is a trigger, not a promise: the fill usually lands a little past it.
Think of the fuse box in a house. You set the level once, and the fuse trips on its own when the current crosses it. You do not stand next to it. A stop loss order does the same job for a position: you place it right after the entry, and it works while you sleep, travel or watch another market. For a long position the stop is a sell order below the market; for a short position it is a buy order above the market.
The mechanics have two separate moments. The first is the trigger: the market trades at or through the stop price. The second is the fill: the order, now a market order, is matched against whatever bids or offers are in the book at that instant. Between those two moments the price can move, and on a fast move it usually does. The next best bid may sit one or more ticks below the trigger, and that is where you are filled. On NQ, the E-mini Nasdaq-100 future, one point is $20 and one tick of 0.25 points is $5, so each tick of slippage on one contract costs $5 (CME Group contract specifications; exchanges can change these values, so check the exchange's contract page or the free futures contract calculator for tick size and tick value).
Hypothetical example
You buy one NQ contract at 20,000 and place a stop at 19,980, 20 points below. The planned loss is 20 points × $20 = $400 per contract. The market falls and trades at 19,980. The stop becomes a market order and fills at 19,979.50, two ticks lower. The actual loss is 20.5 points × $20 = $410. The extra $10 is slippage at the stop.
One practical check before you rely on a stop: ask your broker where the order rests. A stop held at the exchange or on the broker's server keeps working if your computer loses power or connection. A stop that your own platform watches and only sends when triggered stops working the moment that platform disconnects.
Stop market vs stop limit: which one should a futures trader use?
A stop market order makes sure you get out but not at what price; a stop limit order makes sure of the price but not that you get out, and for a protective stop on a leveraged futures contract getting out usually matters more. A stop market order is a stop that becomes a market order at the trigger and fills at the best available price. A stop limit order is a stop that becomes a limit order at the trigger and fills only at the limit price or better. The U.S. Securities and Exchange Commission's investor bulletin on stop orders describes the same trade-off for stock orders, and the logic is identical on futures.
| Question | Stop market | Stop limit |
|---|---|---|
| Does it close the position for sure? | Yes, once triggered | No, only if the limit price trades |
| Is the fill price known? | No, it can be worse than the stop | Yes, at the limit or better |
| In a fast drop or gap | Fills, possibly far past the stop | Can rest unfilled while the loss grows |
| Best use | The protective stop that must work | Exits where a bad price is worse than staying in |
The reason the exit matters more is leverage. A futures contract controls a large notional value for a small margin deposit, so a position left open through a fast move can lose several times the planned amount in minutes. A stop market order accepts a few ticks of bad fill to avoid that outcome. A stop limit order is the right tool when a bad fill is the bigger problem, for example a thin market where the book empties out and a market order would fill many points away, and you would rather stay in than sell into a hole. For a systematic strategy, the choice of stop type is part of the rule set; which stop a futures strategy should use: fixed ticks, ATR, time or trailing covers the rule-side choices in detail.
Why can the fill be worse than the stop price? Slippage and gaps
Slippage at the stop is normal, and a gap across a session break or a fast news move can fill a stop far past its trigger, so the planned loss per contract is a floor, not a ceiling. Slippage is the difference between the price you planned to trade at and the price you were filled at. A gap is a jump between two consecutive traded prices with no trades in between, so a stop placed inside the gap triggers on the first trade past it and fills at that price.
Gaps come from three places. The first is the session break: futures do not trade continuously, and prices can reopen far from the last close after the daily maintenance break or after the weekend; Monday open time and weekend gaps in futures backtests shows how these gaps appear in bar data. The second is scheduled news, where the price jumps several points in one second. The third is a liquidity hole, where the book thins and a modest market order travels many ticks. The joint CFTC and SEC report on the events of 6 May 2010 describes stop orders that triggered during the drop and were then executed as market orders at prices far from the levels their owners had in mind.
Hypothetical example
You hold one NQ contract long with a stop at 19,980. The session closes at 19,990, above the stop. Overnight news moves the market, and the next session opens at 19,950. The first trade is 30 points below your stop, so the stop triggers on that trade and fills at 19,950. The planned loss was 20 points, $400 per contract. The actual loss is 50 points, $1,000 per contract, two and a half times the plan.
For a backtest this has one direct consequence: every stop exit has to be charged slippage, and a stop inside a gap has to fill at the first price past it, not at the stop level. A test that fills every stop exactly at the stop price reports a loss per trade that live trading cannot match. Rerun your strategy with double the usual slippage on exits; if the result collapses, the edge was living in the fill assumption. In AlphaPrime (Valynox) the backtesting applies commission and slippage to every exit, stop exits included, with next-bar execution, so the losses in the report already carry the cost of getting out.
How to place a stop loss order on a futures platform
Placing a stop is the same sequence on every futures platform, and following it in order means no step is skipped. Platforms name the buttons differently, but the order ticket always asks for the same six things.
- Confirm the position. Check the position window: which contract, which direction, how many lots, at what average price. Place the stop against the real fill, not the price you intended.
- Choose the opposite side. A long position needs a sell stop; a short position needs a buy stop. A stop entered on the same side as the position adds to it instead of closing it.
- Choose the order type. Pick Stop (sometimes labelled Stop Market or STP) for a protective stop. Pick Stop-Limit only when you also set a limit offset and accept that the order may not fill.
- Set the trigger price in ticks from entry. Decide the distance as a number of ticks or points, then convert it to a price. On NQ, 20 points is 80 ticks: subtract that distance from the entry price for a long position, add it for a short position.
- Set time in force and link the target. Time in force is the setting that says how long the order stays alive; Day cancels it at the session end, GTC (good till cancelled) keeps it until it fills or you cancel it. For a position held across sessions, choose GTC. If you also have a profit target, link the two as OCO (one cancels the other), so that when one fills the other is removed and you are not left with a naked order.
- Check the working-orders list. The stop is only protecting you when it appears as a working order with the right side, quantity and price. Read all three before you leave the screen.
Two habits save the most trouble. Place the stop in the same minute as the entry, as part of the entry routine, so there is never a position without one. And when you add to or reduce a position, adjust the stop quantity in the same minute, so the working stop always matches the open lots.
How far should the stop be? Testing stop distance in a backtest
Stop distance is a parameter like any other: test a range of distances with commission and slippage charged on each exit, and look for a wide band of distances that behave alike. A very tight stop turns normal bar-to-bar noise into many small losses, each one paying slippage. A very far stop is hit so rarely that the strategy behaves almost as if it had no stop at all. The useful region sits between those two ends.
A sensible way to run the test is to measure distance in units of recent volatility rather than fixed points, because a 20-point stop means something different on a quiet day and on a day after news. The average true range is the usual unit, and the ATR trailing stop rule, its parameters and a futures backtest shows how to set up that test. Kaminski and Lo (2014) studied when stop-loss rules add value and found that the answer depends on how returns behave over time: a stop helps when losses tend to continue and costs performance when prices tend to snap back. That is one more reason to test the distance on your own market and bar size instead of copying a number.
What does a rule look like with no stop at all? The run below is a stand-in, not the subject itself: a simple N Day rule, with no stop, no target and no filter, on ES daily bars from 2019-01-02 to 2025-06-30, long and short, one contract, with $20 commission and $25 slippage charged per trade. It is the one candidate the search kept out of the 1,024 variants it tried, chosen for its return against its drawdown. Picking the kept one after the fact flatters it, so read the numbers as a shape, not a result the rule earned or one a reader should expect.
Source: AlphaPrime product engine (CPU), run 2026-10-31. ES daily bars, 2019-01-02 to 2025-06-30, long and short, 1 contract, $20 commission and $25 slippage per trade.
| Number | Result |
|---|---|
| Net profit (closed trades) | $95,582.5 |
| Max drawdown | $68,465 |
| Trades | 44 |
| Win rate | 65.91% |
| Profit factor | 2.035 |
| Average trade | $2,172.33 |
| Time in market | 93.14% |
Three numbers in the box describe the no-stop shape. Time in market of 93.14% means the rule was almost always holding a position; nothing cut a trade short except the opposite signal. The max drawdown of $68,465 against a net profit of $95,582.5 means the deepest fall along the way was close to three quarters of everything the run finished with. And 44 trades over about six and a half years means each trade carried a lot of weight. Adding a stop to this rule would be a new candidate to test across a range of distances, not a tweak to accept because it makes one number look better.
What a stop loss cannot protect you from: leverage and margin
A stop limits the loss on one trade from one move, while contract count, leverage and margin decide how much of the account that loss is, so the stop distance and the position size have to be set together. Leverage is the ratio between the value a contract controls and the margin you post for it; how futures leverage and margin change backtest drawdown works through that ratio. Margin is the deposit the exchange and broker require per open contract; when the account falls below the maintenance level, the broker closes positions regardless of where your stop sits.
Hypothetical example
The same 20-point NQ stop on a $10,000 account, at $20 per point. The last row is the gap case from the earlier example, where the stop fills 50 points below entry.
| Case | 1 contract | 3 contracts | 5 contracts |
|---|---|---|---|
| Planned loss, 20-point stop | $400 | $1,200 | $2,000 |
| Share of the $10,000 account | 4% | 12% | 20% |
| Gap fill, 50 points | $1,000 | $3,000 | $5,000 |
| Share of the account after the gap | 10% | 30% | 50% |
The table shows why the order of decisions matters. Choose the stop distance first, from the test in the previous section. Then choose the share of the account you accept losing on one trade, and let the contract count fall out of those two numbers; the free position size calculator does that arithmetic from account risk and stop distance. Doing it the other way round, picking five contracts because the margin allows it and then placing the stop wherever the chart looks clean, is how a 20-point stop becomes a 50-point gap on half the account.
Your next step: take one strategy you trade or plan to trade, write down its stop distance in ticks and its contract count, and compute the planned loss and the gap-case loss as a share of your account. If the gap case is more than you would hold through, reduce the contract count before you change the stop.
Frequently asked questions
What is a stop loss in trading?
A stop loss is a resting order that closes a position when the price reaches a level worse than the entry. For a long position it is a sell stop below the market; for a short position it is a buy stop above the market. It works without you watching the screen, and its purpose is to cap the loss from a single trade at roughly a planned amount.
Does a stop loss order always fill at the stop price?
No. The stop price is the trigger. A stop market order fills at the best available price after the trigger, which is usually one or more ticks worse and can be far worse across a gap. A stop limit order fills only at its limit price or better, so it may not fill at all in a fast move.
Does a stop loss order stay active overnight on futures?
Only if its time in force allows it. A Day order is cancelled at the end of the trading session; a GTC (good till cancelled) order stays working until it fills or you cancel it. For a position held across sessions, set the stop to GTC and confirm it still appears in the working-orders list after the session break.
Should a stop loss be set in ticks, points, dollars or percent?
Set it in a unit that connects to the market's movement, then convert it to a price. Many systematic traders use a multiple of the average true range, because a fixed point distance means something different on quiet and volatile days. Convert the final distance to dollars per contract to size the position, and test the distance in a backtest with slippage charged on each exit.
What is the difference between a stop loss and a stop limit order?
A stop loss, in the usual sense, is a stop market order: at the trigger it becomes a market order and fills at the best available price. A stop limit order becomes a limit order at the trigger and fills only at the limit or better. The first makes the exit certain but not the price; the second makes the price certain but not the exit.
References
- U.S. Securities and Exchange Commission. Stop, Stop-Limit, and Trailing Stop Orders (Investor Bulletin). https://www.investor.gov/introduction-investing/general-resources/news-alerts/alerts-bulletins/investor-bulletins-15
- CME Group. E-mini Nasdaq-100 Futures contract specifications (contract size $20 × index, minimum tick 0.25 index points = $5.00). cmegroup.com/markets/equities/nasdaq/e-mini-nasdaq-100.contractSpecs.html
- Kaminski, K. M., & Lo, A. W. (2014). When Do Stop-Loss Rules Stop Losses? Journal of Financial Markets, 18, 234–254.
- Staffs of the CFTC and SEC (2010). Findings Regarding the Market Events of May 6, 2010. Report to the Joint Advisory Committee on Emerging Regulatory Issues, September 30, 2010.